Targeting the tumor: New procedure injects radiation directly into liver

Wednesday

Nov 28, 2007 at 12:01 AMNov 28, 2007 at 5:42 AM

Doctors are taking an inside track to treat liver cancer. For more than a year, three Peoria doctors have been performing selective internal radiation therapy at OSF Saint Francis Medical Center.

Ryan Ori

Doctors are taking an inside track to treat liver cancer.
For more than a year, three Peoria doctors have been performing selective internal radiation therapy at OSF Saint Francis Medical Center.
SIRT is a cutting-edge treatment that attacks tumors from the inside of the liver. It allows higher doses of radiation to be concentrated on small areas of the organ.
"It gives a very high dose of radiation into the tumor," said Dr. Bob Smouse, an interventional radiologist with Central Illinois Radiological Associates. "The dose that's given to the tumor is so great that if you tried to do it with external beam radiation, it would just fry the body. You couldn't get enough radiation into the tumor without killing the liver.
"By going into the tumor and injecting these (radioactive) beads, the radiation distance is only about half an inch. We inject between 20 and 60 million beads. It's sucked up by the tumor and the tumor gets an inordinately high dose of radiation while the surrounding liver gets a very small amount of radiation."
Candidates are chosen by Dr. James McGee, a radiation oncologist at St. Francis. He also sets the radiation dosage.
The catheterization procedure is performed by Smouse and Dr. James Swischuk, another interventional radiologist at CIRA.
SIRT is not a cure for cancer, but it appears to improve quality of life.
Because of the liver's crucial role in detoxifying the blood, tumors there can dramatically shorten a patient's life. For patients with cancer in multiple organs, this treatment can extend life expectancy by months or even years.
"If we think the liver is what's going to kill them, we'll go ahead and treat the patient even if (tumors) have spread elsewhere in the body,"
Smouse said. "We're not curing it. We're just trying to slow it down from taking over the liver."
McGee became aware of SIRT while helping a good friend research possible treatments for primary liver cancer. His friend, a neurosurgeon, died after it was discovered his cancer was too advanced for SIRT.
But McGee later brought medical experts to Peoria to conduct training.
The closest city offering SIRT is believed to be Chicago. McGee said approximately 25 patients have been treated in Peoria since SIRT was introduced here, with about 75 percent seeing positive results.
SIRT was first developed in Australia in the 1980s. After years of refinement, its use began in the United States about five years ago.
Candidates for SIRT are patients with several tumors throughout the liver but who maintain liver function.
"When you talk about many liver tumors such as multiple metastases to the liver and even primary cancers to the liver, usually these are fairly diffuse throughout much of at least one lobe of the liver," McGee said. "If you tried to treat that with external radiation, you would do as much harm as good."
SIRT is a two-hour procedure that requires the patient to remain hospitalized overnight.
If pre-testing indicates acceptable liver function, McGee sets a dosage of radioactive material, which is attached to the polymer beads – and refers the patient to a radiologist.
The radiologist inserts a catheter into the femoral artery near the groin. Using fluoroscopy, basically a real-time X-ray, the radiologist guides the catheter into the artery that feeds the tumors.
The liver is a unique organ in that it receives a blood supply from both arteries and veins. That allows the injected arteries to be blocked off after 20 to 60 million radioactive beads, or SIR-Spheres, enter the tumor.
"When we inject this into it, we tend to block off the arteries that we're injecting into," Smouse said. "So we need an organ that has two blood supplies so we can block off one and not the other."
The microspheres, each one-third the diameter of a strand of hair, attach themselves to tumors. With a half-life of 64 hours, the SIR-spheres put off intense radiation only in and immediately around the tumors. Each bead sends out radiation extending less than half an inch.
"Once they're lodged in those blood vessels, they're in approximation to the cancer cells and they give the radiation off very locally," McGee said. "They can damage the cancer cells, but they don't throw radiation far enough to really affect the normal liver tissue."
The microscopic beads remain permanently in the body. SIRT side effects, such as nausea and malaise, usually are relatively minor compared with other forms of treatment.
Ryan Ori can be reached at rori@pjstar.com.

Community Info

Original content available for non-commercial use under a Creative Commons license, except where noted.
The Lake News Online ~ 918 N. Business Route 5, Camdenton, MO 65020 ~ Privacy Policy ~ Terms Of Service